CHELYABINSK, RUSSIA
— A FEW years ago the city fathers of this grimy industrial center east of the Ural mountains erected an imposing statue of the nuclear physicist Igor Kurchatov, a metallic model of the atom circling above his head.

The sculpture is a rare public acknowledgment of the most tightly kept secret of this cluster of defense plants and metal mills - the nearby presence of the Soviet Union's first atomic-bomb factory. Kurchatov came here at the end of World War II to found and run the plutonium production plant and nuclear-waste reprocessing facility that grew into a secret city of about 100,000 residents still known only as Chelyabinsk-65.

But the 3.2 million residents of this region may not share in the public plaudit for Kurchatov. For them his legacy is decidedly mixed. Since 1949, the bomb factory has been dumping highly radioactive waste into the surrounding environment, most spec- tacularly in a massive accident in 1957 whose exact nature and extent was not publicly acknowledged until less than two years ago. Even now, local officials describe the huge accumulation of radioactive waste awaiting treatment here as an environmental disa ster waiting to happen.

Tomorrow, Secretary of State James Baker III will be the first senior United States official to visit the secret cities of this once "closed" region. He is scheduled to visit Chelyabinsk-70, a smaller city founded in 1955 as the second major Soviet major facility for designing nuclear weapons.

Mr. Baker is here to dramatize the concern in the US over the fate of the thousands of nuclear scientists who Western governments fear could sell their skills to would-be nuclear powers in Iran, Iraq, and elsewhere. (Keeping Soviet science productive, Page 7.) He is also expected to examine the problem of reprocessing the nuclear material of the tens of thousands of warheads atop Soviet tactical and strategic weapons.

The lack of such reprocessing facilities, of which the Mayak plant in Chelyabinsk-65 is the largest, is a key bottleneck to Russian pledges to destroy those weapons and prevent them from being sold to third countries.

What Baker will find, judging from the information provided by local officials during a recent visit here, is that the bottleneck is completely clogged and cannot be cleared without large-scale foreign assistance. (Apparently prompted by the Baker visit, the Russian government earlier this week officially opened Chelyabinsk to foreigners.)

According to Lev Stobbe, head of the environment committee of the Chelyabinsk regional government, the last of the five reactors producing plutonium at Mayak ceased operation two years ago. But according to a report Mr. Stobbe helped prepare for the Russian government, 25 tons of plutonium are stockpiled there.

Mayak was set up to produce plutonium from spent nuclear fuel produced by Soviet-designed BBR-440 nuclear reactors in use here and in several Eastern European countries, as well as from Soviet nuclear submarines and nuclear-powered ships. The radioactive waste awaiting treatment at Mayak is equal to more than a billion curies of radiation - what Stobbe describes as "20 Chernobyls," referring to the Soviet nuclear power plant that blew up in Ukraine in 1986.

Of this amount, some 600 million curies of highly radioactive materials are stored in liquid form and another 500,000 tons as solids. Given Mayak's capacity to reprocess the waste for use in fast-breeder reactors or into forms for longer-term storage, it will take decades to deal with what is already sitting there, says Stobbe.

The present storage system, which includes eight water reservoirs built in the riverbed of the diverted Techa River, "is practically exhausted," according to the Russian government report.

"The main danger is that all these radioactive lakes are leaking into underground waters," says Pavel Bolshakov, an environmental activist and member of the regional legislature. That water flows into Siberian rivers that dump into the Arctic Ocean, making this a "danger to the world," he warns.

Such concerns take on added drama against the historical backdrop of what is known in public literature as the Urals Nuclear Accident. Until April 1990, the exact nature of this event was a matter of speculation, although numerous books and articles have been written based on information leaking out over the years.

It is now known that on September 29, 1957, a storage tank containing highly radioactive waste, heated by on-going low-level reactions, blew up, and northerly winds carried the radioactive dust over an area 19 miles wide and 150 miles long. A still-undetermined number of people died - in the tens, says Stobbe - and an estimated half-a-million people received dangerous dosages of radiation. Some 350,000 of these have been identified for potential assistance, including 314,000 civilians, 24,000 servicemen,

and 15,000 nuclear workers.

This accident came on top of the uncontrolled dumping of waste into the Siberian rivers between 1949 and 1951. It was followed by another accident in 1967, previously unrevealed, when a drought exposed the radioactive silt at the bottom of Lake Karachai, which remains the main storage area for high level waste. A tornado hit the lake, spreading the silt into the air. "Luckily it moved according to the path of the previous radioactive trace," says Stobbe. Since then, the lake has been partially covered wi th concrete, but authorities worry about water draining into the water table.

Vast tracts of land remain closed and contamination is an ongoing problem. An Israeli engineer involved in building a slaughterhouse in Chelyabinsk revealed that he was required to add a radioactive testing lab to the design.